Method of forming metal



Apr. 3, 1923. 1 ,450,648

H. A. SCHWARTZ METHOD OF FORMING METAL Filed May 1, 1922 WITNESSES nvvmron 17R. Vyalfier Harry 14,50 wartz ATTORNEYS Patented Apr. 3, 1923.

UNITED 's'rA-ras 1,450,648 PATENT OFFICE.

HARRY A. SCHWARTZ, OF DEFIANCE, OHIO.

METHOD OF FORMING METAL.

Application filed May 1, 1922.- Serial No. 557,527.

- a citizen of the United States, and a resident of Defiance, in the county of Defiance and State of Ohio, have invented a new and Im proved Method of Forming Metal, of which the following is a full, clear, and exact descri tion.

his invention relates to an improved method of forging or forming metals, an object of the invention being to provide a method in which the part being formed, in itself functions as a circuitclosing means to control the time of the forging or forming blow.

A further object is to provide a method of the character stated, in which the electric conductivity of the metal is utilized to control the time of the forging orforming blow.

It is a well known fact that there is a wide difference in conductivity or resistance between metal in a molten state and in a solid state, and I utilize this factor in controlling the fiow of electric current to cause the operation of electric means to insure the timing of the forging or forming blow at proper interval; hence utilizing the part being formed in itself to control the operation of the ram or mechanism for forging or forming the part, resulting in an automatic control which is uniform and insures uniformity of the parts or forgings.

Certain metals, such as cast iron, aluminum, brasses, etc., are not ductile and cannot be forged or formed excepting at or around theperiod of solidification and then within well defined limits. It is practically or commercially impossible to judge this period uniformly and accurately by any means excepting by automatic control actuatedby the temperature or electric resistance variation of the metal when at the proper forging or forming period. The forming mechanism, controlled by action of the metal when at the proper forging or forming state, will operate absolutely at the proper interval over extended operating periods. This automatic control of the forming mechanism will produce an absolutely uniform forging or part as regarding its physical properties, and insures a minimum spoilage in manufacture.

It is to be understood that my invention has to do with the automatic control of the forging or forming mechanism by action of the part or forging itself.

Throughout the. specification I shall employ the term forming as indicative of the action in forging or forming a metal part in a metal die, but I would have it understood that this term is employed in its broadest possible sense to indicate the use of any means to form a part.

As above stated, it is a well known fact that there is a Wide difference in electric conductivity between molten metal and solid metal. There is a sharp curve in the degree of co-nductlvity between the metal in the molten stage and as it solidifies, and it is understood that this factor is to be utilized as a circuit controlling means, whereby the forging or part forming mechanism is set into operation when the molten metal is solidifyin It will tins be seen that with my improved method, the forging or part itself functions to control the timin of the forming mecha-. nism, by utilizin t e electric conductivity of the metal itse f.

With these and other objects in view, the invention consists in certain novel steps in the method, as will be more fully hereinafter described and pointed out in the claims.

In my pendin application for method of casting, filed Fe ruary 16, 1922, Serial No. 537,024, I disclosed a process of casting in which the casting itself functions as a circuit closing means to time the ejection of the casting, and the present invention is designed to cover the idea broadly, of timing the operation of the metal forming means, or in other words, the movement of one forming member relative to the other to shape the metal.

The accompanying drawing is a view partly in section and partly in elevation, but mainly diagrammatic, illustrating an apparatus capable of carrying out my improved method.

A and B represent metal forming members and for convenience of description, we will assume that the lower member B represents a female die member, and the upper member A, a plunger, or rain, which is operated by a pneumatic apparatus C, and connected to the plunger rod 1 thereof. This pneumatic apparatus C, is controlled by rotary valve 2 movable by rack bar 3 to control the direction or flow of the air, and

correspondingly control the movement of the ram A. This bar 3 is caused to move by solenoids. l) and It when the latter are energized. as will more fully hereinafter appear. The detailed structure of the operating means forms no part of the present invention and hence. need not he dcscrihed in detail.

In the female die member B, I provide a pair of electric. contacts 4, 4 which a re preferahly. although not essentially, of tungsten wire mounted in plugs 5 of insulation, preferahly though not essentially of alundum. The inner ends of the contact 4 connnuni: cate with the interior of the member B and are in direct contact with the metal (3 when the latter is introduced into said member B.

The electrical resistance of the metal va ries directly as the temperature, and 15 therefore a good indication of the forming, or forging condition of the metal. The resistance curve for metal, shows a sharp break at the point of solidification, for 1nstance, a typical brass metal will show a difference in electrical resistance value of nearly 3 to 1 when changing from the molten stage to the solid. A good brass may show in the liquid state a resistance of 40 micro-ohms per centimeter cube, and when just solid, a resistance of 17 microohms per centimeter cube. This resistance continues to decrease with further reduction of temperature.

I utilize this relative conductivity of the metal as a timing medium for the operatlon ormovement of the ram A, as will be explained.

The contacts 4, are included in a relay circuit with a solenoid, F, and the source of electricity 7 so that when the metal 6 solidifies to a point where it will permit the necessary electric current to flow thereto, it will operate to close the circuit to the solenoid F and energize the latter.

8 represents a movable contact which, when the solenoid F is energized will be moved thereby to close a circuit including a switch 9, solenoid D and electricity source 10, so that the rack bar 3 will be moved in a direction to cause the ram A to be forced downwardly to shape the metal 6 in member The movement of the contact 9 may be controlled by various mechanisms, but for purposes of illustration I have shown lugs 11 and 12 on one side of the ram A and it will be noted that these lugs 11 and 12 function to move the contact 9, the upward movement of the ram bringing lug 12 into position to close contact 9 and the downward movement of the ram A bringing lug 11 in position to open the contact 9.

On the opposite side of the ram A, I provide lugs 13 and 14 and these lugs control the movement of a contact 15, and I would have it understood that these lugs 11, 12, 13 and 14 are so arranged that the circuit of contact 5) is closed before the circuit of coiltact l? is open and the circuit of contact 15 is closed just prior to the opening of the cir cuit. ol'.contact 9. The parts illustrated are simply for illustration as the structural dctails can be varied and standardized.

The contact 15 is included in an electric circuit with the electricity source 10 and the solenoid l] so that when said contact 15 is closed by the downward movement of the, ram A, the solenoid E will be energized, move the bar 3 to reverse the valve 2 and cause the ram A to move upwardly. In both of the circuits for the solenoids, D and E, I provide adjustment contacts 16 and 17 respectively which may be manually operated to control or adjust the. position of the ram A.

It is to be understood that after the metal (3 is shaped in the member B, it will he removed or ejected in any approved manner, which operation will preferably be automatic, so that at each completion of the oper ation of metal forming a new supply of molten metal will be introduced into the mold member B. The operation is as follows:

Assuming the parts to be as shown in the drawing with the molten metal 6 in the member B as soon as this metal 6 solidifies to a sufficient degree, it will serve as a circuit closing means to permit the solenoid F to be energized, thus moving the contact 8 and closing the circuit to solenoid D. The ram A will then move downwardly as rapidly or as slowly as may be desired and will shape the metal in member B; as the member A completes its downward stroke, it will close contact 15 and open contact 9, thus energizing contact E to cause a reversal of the movement of the ram A to bring the ram upwardly and the upward movement of the ram A will function to close and open contact 15.

It is to be understood that these contacts 9 and 15, will be so timed in their movement as to properly function in opening and closing the circuits for a perfect operation. While I have illustrated a form of apparatus and referred to upward and downward movements of the ram it is obvious that the invention is not limited to such movements as the movements may be horizontal or in angle and the great variety of apparatus may be employed, the only essential being that at least one of the members is movable toward the other to form a metal and the metal itself functions as a circuit closing means to control the movement of the forming mechanism.

I claim:

1. The herein described method, consisting in introducing molten metal into one ee s forming member and'utiliaing the electric conductivity of said metal to control move: ment of the other forming member.

2. The herein'described method of form ingnietal, consisting in, introducing molten metal into a die, and controlling. the opera tion of the fol-min mechanism by the electric conductivity 0? the metal to be formed.

3. The herein described method of form-- ing metal consisting in introducing molten metal'into a die, and controlling the time of operation of the formin mechanism by the electric conductivity 0 formed.

4. The herein described method of forming metal, consisting in introducing molten metal into" a die, automatically operating the forming mechanism, and timing the operation of the forming mechanism in accordance with the electric conductivity of the metal to be formed.

5. The herein described method of forming metal, consisting in introducing molten metal into a die, operating the forming ll mechanism when the metal reaches a predethe metal to be tel-mined solidity, and controlling the time cooperation of the forming mechanism 6. The herein described method of forming metal, consisting of introducin molten metal into a die, allowin the meta to cool to the proper state of so idity, and controlling the operation of the forming mechanism by the electric conductivity of the metal.

7. ,The herein described method of form- I,

ing metal, consisting in introducing molten metal into a die, allowingthe metal to cool to a predetermined temperature and controlling the operation of the forming mechanism by the electric conductivity of the metal.

8.- In combination with the metal forming means, electric conductors in contact with the metal to be formed whereby the metal functions as a circuit opening and closing means to control the operation of the forming mechanism.

HARRY A. SCHWARTZ. 

